[Coco] Early disk drive cabling

[Al Hartman]

Here are some links that might be helpful to you...

http://www.coco3.com/community/2009/09/coco-drives

http://www.vintage-computer.com/vcforum/showthread.php?25767-Floppy-Drive-on-Tandy-COCO3

I would make a cable with 5 connectors:

1st Connector - to Disk Controller (all pins)
2nd Connector - Drive 3 (pull pins 10, 12, 14) (Normally Pin 6 is drive 
select 3, but Tandy decided to use pin 36 which is side select.
                                                                           I'm 
not clear how the cable needs to be pinned for double sided drives. a Drive 
3 needs
                                                                           the 
pad for pin 36 cut and jumpered to pin 6.)
3rd Connector - Drive 2 (pull pins 10, 12, 36)
4th Connector - Drive 1 (pull pins 10, 14, 36)
5th Connector - Drive 0 (pull pins 12, 14, 36)

I believe this is correct. To double check, open your drive to see if pin 36 
is cut and jumpered to pin 6.

I'm also pretty sure that model drive supports only 35 tracks.

I have one I'd like to sell if you are looking for another.

-[Al ]-


-----Original Message----- 
From: Mark J. Blair

I'm putting together an early silver CoCo system in an original-like 
configuration. I just received one of the early 26-3022 drives, in a silver 
case, made by TEC, with the big lever at the lower right corner to release 
the drive door. I also have a 26-3022 controller on the way, purchased 
separately.

I'll need to fabricate a ribbon cable. While I had the drive open to clean 
the head, I didn't find any drive ID jumpers. Did the early 26-3022 drive 
systems have contacts pulled from the individual edge connectors on the 
ribbon cable in order to manage drive IDs, as was done on some other TRS-80 
internal cabling? Did the basic single-drive system originally include a 
cable with edge connectors for additional drives, or did the cable need to 
be replaced when adding drives?

-- 
Mark J. Blair, NF6X <nf6x at nf6x.net>
http://www.nf6x.net/


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